Triple DES products hitting market

[Lyle_Seaman at transarc.com]

Anonymous <nowhere at bsu-cs.bsu.edu> writes:
> Cylink Triples Encryption
> by Sharon Fisher
...
> Cylink's Cipher/Decipher-HSi offers triple-DES, which encrypts DES
> data three times, and gives the 56-bit key the effect of a 112-bit key,
> according to the company, based here. The triple-DES approach makes 
> the Cylink product more secure than the government's proposed Clipper 
> system, which uses an 80-bit key, the company said.

Umm.  How does this make a system much more resistant to an attack
like Weiner's?  If there's only a single 56-bit key, the brute-force
known-plaintext + ciphertext attack still only needs to do < 2^56
trial encrypt/decrypt operations.   

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